Objects in Motion | Grade 4 | Unit 2 - Concept 1 - Lesson 2 | Science

شرح ساينس الصف الرابع الابتدائي لغات - الفصل الدراسي الأول شرح ساينس رابعة ابتدائي - ترم أول لينك تحميل الملزمة https://drive.google.com/file/d/1Dtnd... لينك تليجرام https://t.me/mrahmedelbashagroup In This lesson: How do objects move? There are two forces that cause objects to move which are: Pushing force Pulling force Example: A man pushes a wheelbarrow. Example: A child pulls a toy car. The relation between motion with balanced and unbalanced forces: Balanced forces Unbalanced forces If there are balanced forces act on an object, so this object will not move. Example: In the tug-of-war game, if the two teams are pulling the rope with equal forces. This means that, the forces that act on rope are balanced (equal) forces. So, the rope will not move. If there are unbalanced forces act on an object, so this object will move. Example: In the tug-of-war game, if one team is pulling the rope with a greater force. This means that, the forces that act on the rope are unbalanced (unequal) forces. So, the rope will move toward the team with the greater force. Objects in Motion How do we know an object is moving? An object is in motion if its position changes from one place to another, even if this change can't be seen. The change in position of an object is compared to something else that is not usually moving (fixed point). Some motions are easy to see, such as: What are the forces that affect the bag when you lift it? The force of gravity pulls your bag downward. The force of your arm pulls your bag upward. The pulling force of your arm is greater than the pulling force of the gravity (two unbalanced forces). So, the bag moves up toward the greater force. Is there any force affects objects when they are not in motion? 1. When you sit on a chair : The force of the gravity pulls you downward. The chair exerts force that pushes your body upward. The pulling force of the gravity is equal to the pushing force of the chair (two balanced forces). So, there is no motion due to the two balanced forces that hold you in the chair. 2. When a book is put on a table : The force of the gravity pulls the book downward. The table exerts force that pushes the book upward. The pulling force of the gravity is equal to the pushing force of the table (two balanced forces). So, there is no motion due to the two balanced forces that affect the book. بالتوفيق مستر احمد الباشا